Fuel metering control



Dec. 16, 1952 E. A. MALI'CK FUEL. METERING CONTROL 2 SI-lEETSf-SHEET 1 Filed April 20, 1948 THERMOCOUPLE DETONATION INDICATOR a N w T c n n U \u\\ w '1', cw L s 0 Y R A T L N E O m. 9.. m um U J Fv 5 7 A 7 4 3 3 6 3 3 3 I INVENTOR. E MI L A. MALICK A T TORNEYS Dec. 16, 1952 I E. A. MALICK 2,621,642

' FUEL METERING CONTROL Filed April 20, 1948 2 sHEE'rs--sHEET 2 ||9 12: E 1 3 MOTOR iGEAR BOX I24 IN V EN TOR.

E MIL A. MALICK BY 2 X ATTORNEYS Patented Dec. 16, 1952 FUEL METERING CONTROL Emil A. Malick, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware Application April 20, 1948, Serial No. 22,170

This invention relates to a fuel metering system for automatically regulating the fuel-air ratio:

in a fuel mixture supplied to an internal combustion engine. 5

Carburetors utilized in aircraft and other internal combustion engines are designed to pro-' vide a predetermined fuel-air ratio at each engine power, and the engine power is generally proportional to air flow. Within the idling range of the engine, the fuel-air ratio is decreased in a linear manner as the power is increased. In the cruising range, the fuel-air ratio remains substantially constant as the power is increased while, in the high power range, the fuel-air ratio is progressively increased as the power is increased, in accordance with a function determined by the engine design, the fuel to be used, and other factors. Finally, at extremely high powers, the fuel-air ratio is again substantially constant as the power is increased.

In the high power range, the fuel mixture must be enriched as the power is increased in order to prevent an excessive increase in engine temperature and in order to suppress detonation. This is ordinarily dcneby designing the carburetor so as to supply a, sufi'iciently rich fuel'mixture that neither detonation nor excessive engine temperatures are encountered, regardless of the temperature ,or other conditions under which the engine is operated. In the usual carburetor, two settings are provided, one for a rich fuel mixture, and the other-for a lean fuel mixture. However, any fuel metering structure which will permit only a finite number of fuel-air ratios, at a given engine power in the high power range, will introduce. compromises affecting either fuel economy or engine. reliability and life, or both simultaneously. It is also apparent that the smaller the number of selective fuel-air ratios, the greater becomes the degree of compromise which must be accepted. Accordingly, at each power within the high power range, the carburetor maintains a fixedfuel-air ratio in the rich setting, and'som'etimes in the lean setting, which is high enough to prevent detonation, and excessive engine temperatures under the worst conditions which could be'encountered in operation of the engine. T

. It will be apparent that substantial savings in fuel may be effected by. providing means for automatically adjusting the fuel-air ratio to the 13 Claims. (Cl. 123-119) optimum value for prevailing engine and atmospheric conditions. This would enable the use of a leaner mixture than that provided by the carburetor under most operating conditions. As an example, low atmospheric temperatures will cause the engine temperatures and the tendency toward detonation to decrease thereby enabling the use of a leaner fuel-air mixture. In addition, variations in the characteristics of the fuel, spark setting, valve timing, and other factors also permit the use of a leaner mixture. Further, the use of unnecessarily rich mixtures, as frequently introduced by present carburetor under ordinary operating conditions, oftentimes causes torching of the exhaust, or substantial power losses resulting from introduction of excessive fuel to the engine cylinders. Torching may result in damage to the exhaust collector pipe or adjacent parts, and is very disadvantageous in many respects, particularly in the operation of military aircraft, since it permits such aircraft to be readily detected at night.

It is 'an' object of my invention to eliminate the problem of fixed fuel-air ratios by varying the fuel-air ratio as a function of the requirements for suppression of detonation or maintenance of proper engine temperature, particularly in the high power range of engine operation. It as further object of the invention to provide fuelmetering apparatus to regulate the fuel-air ratio so that there will be no danger of detonation or overheating due to excessively lean mixtures'of fuel and air.

It is a still further object of the invention to minimize'the'danger of torching of the exhaust or large power losses due to excessively rich mix-'- tures. 1'

Various other objects, advantages and features of the invention will become apparent fromthe following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic circuit diagram of'iny novel fuel metering apparatus; I 2

- Figure '2'i's a schematic circuit diagramio'f' a time-delay unit utilized in Figure 1; and

Figure 3iis a view illustrating a featureof the circuitof'Figu're2. 'Referring'now to thedrawings in detail, .and particularly to Figure' 1; I have disclosed a fuel control valve "l0 having a tapered portion II which cooperates with an orifice |2 to control the delivery of fuel to the cylinders of an internal combustion engine and thereby to vary the fuelair ratio. In some instances, a rotary or other type of valve may be substituted for the structure shown. A lever I3 is pivoted to the valve I and this lever is pivoted, in turn, to an arm M which may be rotated by a reversible electric motor [5. The construction of the motor and valve is such that rotation of the motor in one direction opens the valve l0 and thereby enriches the fuel mixture whereas rotation of the motor in the opposite direction closes the valve I0 and lean out the fuel mixture.

The operation of the motor is controlled jointly by a detonation meter l5 and a thermocouple I? which constitute, respectively, devices for sensing detonation in one or more cylinders of the engine and for sensing engine temperature. A suitable detonation meter is shown in the copending application of D. R. de Boisblanc, Serial No. 548,757, filed August 9, 1944, now Patent No. 2,448,323, issued August 31, 1948, and it will be understood that this meter provides an electrical current, the voltage of which is representative of the intensity of detonation in one or more engine cylinders. The thermocouple |l maybe of conventional construction and constitutes a device for providing an electrical current which is proportional to some desired indication'of the engine temperature, such as the temperature of the cylinder heads or cylinder bases.

The electrical output of the detonation meter I6 is fed through conductors |8 to the coil of a solenoid l9. The corev of the solenoid carries a contact bar 2| which is engageable with two contact sets 22 and .23, the contacts '23 being closed when detonation of a predetermined intensity is occurring in the cylinder, and the contacts 22 being closed when no detonation is occurring in the cylinder. The core 20 is biased inwardly toward the solenoid H! by a spring 24 so that, under certain conditions, the bar 2| may occupy a position intermediate the contacts 22 and the contacts 23.

A unit similar to that already'described in connection with the detonation meter I6 is provided for the thermocouple N. This unit includes conductors 26 for feeding the electrical output-of the thermocouple to. the coil of a solenoid 21, the core 28 of whichcarries a bar 29 which is engageable with a set of contacts 30 when the engine temperatures are toolow and which is engageable with a set of contacts 3| when the engine temperatures are too high, the core 2.8 being biased toward the solenoid 21 by a spring 32 so that the bar may occupy a position intermediate the contacts 30 and 3| when the engine temperature is within a predetermined operating range.

When excessive detonation occurs in the cylinder of the engine, contacts 23' are closed and a voltage is applied across a set of terminals 33, 34 by a circuit which includes contacts 23, a current source 35, a conductor '36 and a conductor 31. The voltage appearing across terminals '33, 34 is applied to the motor |5 through a main control switch 38, a thermostatic switch 39, an intermittent switch 40, the contacts 4| of asolenoid 42, motor terminals 43, and a time delay switch 44. Assuming that all of the switches are closed, the voltage across terminals 33, 34 causes operation of the motor in the proper direction to slowly open valve I0 in a progressive manner, thereby continuously enriching the fuel mixture fed to the engine until the detonation ceases. Thereupon, contact bar 2| is disengaged from contacts 23 and the motor circuit is broken. Similarly, when high engine temperatures are encountered, the bar 29 engages contacts 3| thereby applying a voltage across terminals 33, 34 through a circuit which includes contacts 3|, a current source 45, a conductor 41, and a conductor 43, this voltage causing operation of the motor l5 in the proper direction to open the valve I0 and enrich the fuel mixture until the excessive engine temperatures are lowered. Thereupon, contact bar 29 is disengaged from contacts 3| and the motor circuit is broken.

Similar circuits are provided for causing rotation of the motor |5 in opposite direction when excessively low engine temperatures are encountered or when no detonation occurs in the engine cylinder so that the valve I0 is progressively closed to lean out the fuel mixture. These circuits, however, differ from those already described in that they are disabled by energization of either one of a pair of relays 50 and 5|, for reasons to be hereinafter explained in detail. Thus, when no detonation is occurring, the bar 2| closes a circuit which includes a current source, 53, contacts 22, normally closed contacts 54 of relay 5| normally closed contacts 55 of relay 5|, and the conductor 43. Although contacts 54, 55 are referred to as normally closed contacts for convenience, it will be noted that they are not biased to closed position. Assuming that both sets of relay contacts are closed, as shown, a voltage is applied across terminals 33 and 34 which is of the proper polarity to operate motor |5 in such direction as to close the valve l0 and lean out the fuel mixture.

Similarly, when the engine temperature becomes too low, contact bar 29 engages contacts 30 thereby closing a circuit which includes a current source 58, contacts 3|), normally closed contacts 59 of relay 5|, normally closed contacts 60 of relay-55, terminals 33,34 and the conductor 47. Assuming that the contacts of relays 50 and 5| are closed, this circuit applies a voltage across terminals 33 and 34 which causes the motor l5 to operate in the proper directionto close valve l0 and lean out the fuel mixture.

It will be noted that relay 50 is provided with a coil 63 which is connected in circuit with a resistor -64, current source 35, contacts 23, and a conductor 65. Accordingly, when detonation occurs in a cylinder, and contacts 23 are closed to enrich the fuel mixture, the coil 63 is energized and the relay 53 is actuated to open contacts 54 and 60. This disables the described circuits for leaning out the fuel mixture until contacts 54 and 50 are again closed in the manner hereinafter described. Similarly, the relay 5| is provided with a coil 31 which is connected in circuit with a resistor 68, current source 46, contacts 3|, and a conductor 60. Accordingly, when contacts 3| are closed responsive to excessive engine temperatures, and the valve I0 isoperated to enrich the fuel mixture, the coil 6'! is energized thereby operating relay 5| and breaking contacts 55 and 59. This disables both leaning out circuits until the contacts 55, 59 are again closed in the manner hereinafter described.

The relays 50 and 5| have a pair of'solenoids i0- and H associated therewith, respectively, and each solenoid, when actuated, moves the armature of its associated relay so as to close the normally closed relay contacts. The coils of the solenoids 10, 1| are connected-in series with each other and with thecoil of the solenoid 42. When the latter solenoid is energized, the valve operating lever I4 is rotated a sufficient distance in a counter-clockwise direction to completely open valve I and provide a rich fuel mixture for the engine. The extent of richness can be limited to the rich setting of the carburetor if desired, or a value slightly richer than that provided by the rich setting of the carburetor. The solenoids 42, I0 and II are all actuated simultaneously when current is fed to the coils thereof through a pair of conductors I2, 13 forming a part of a power change sensing unit 14. Solenoids I0 and II are energized without actuation of solenoid 42 when current is supplied through conductors 15, I6 from battery I1 and the time delay switch unit 44, the operation of which will be further described hereinafter. It will be understood'that energization of solenoids 10, 'II by either of the described circuits causes closure of contacts 54, 60 and contacts 55, 59 with the result that the leaning out circuits controlled by contacts 22 and contacts'30 are in readiness for operation should the engine temperature fall below a predetermined value and no detonation be present in the engine cylinder, or cylinders, to which detonation meter I6 is attached.

The power change sensing unit 14 includes a control lever 80 which is moved laterally when a. pressure differential exists between two bellows chambers 82 and 83. In the case of an aircraft engine, chamber 82 may be connected through line 84 with compensated or uncompensated scoop suction and chamber 83 may be connected through a line 85 with boost suction. The term boost suction herein refers to suction forces created by a. small venturi located within the main one, exit being near the throat of the main venturi so as to augment the suction. Similarly, the term compensated or uncompensated scoop suction refers to corrected metering forces below prevailing atmospheric pressure which is obtained by the automatic mixture control compensating for changes in barometric pressure with changes in airplane altitude. Accordingly, the displacement of lever 80 is proportional to the pressure differential between chambers 82, 83 which, in turn, is proportional to the power level of the engine. A pair of springs 86, 81 are connected, respectively, between a collar 88 carried by the control lever and a pair of dash pots 89 and 90. Each of the dash pots is mechanically connected through a lost-motion connection 9I to the collar 88 so that sudden movements of the control unit 80 are effectively sensed.

A set of contacts 93 is carried by control lever 80,- this set of contacts cooperating with contacts 94, 95 which are mounted on the respective dash pot units 89, 99 and which are interconnected by a conductor 96 leading to one terminal of a current source 91, the other terminal of which is connected to conductor 13. The contacts 93 are connected by a conductor 98 and a switch 99 to conductor 12. The vmovable arm I00 of a switch IN is mechanically connected to the control lever 80 by a link I02 and electrically connected to the conductor 98 by a lead I03. The switch includes two stationary contacts I04, I05 and these contacts are interconnected by a wire I06 which leads to the conductor 96.

When the engine is operating within a predetermined power range, arm IN is positioned between contacts I04, I05 and switch |9I is open. If the engine power rises above or falls below this predetermined range, either contacts I00,

I04 or I00, I05 are closed with the result that solenoids 42, I0 and II are energized. Accordingly, relays 50, 5| are reset, arm [4 is raised to feed a rich mixture to the carburetor, and the automatic control system is disabled until switch IOI is opened. This occurs when the power level of the engin is once again within the predetermined range of automatic operation. Preferably and advantageously, this predetermined power range corresponds to the wellknown high power range of the engine.

When the engine power is within the predetermined range and switch IOI is open, power changes occur frequently which are of insufiicient magnitude to close switch I0 I. Such power changes effect momentary closure of contacts 93, 9 4 or 93, 95 demnding upon whether the power is increased or decreased, the closure of said contacts causing a momentary energization of solenoids 42, 10 and II. For example, if lever 89 moves toward dash pot 90, lost motion connection 8'! permits momentary engagement of contacts 93 and 95. After such momentary engagement, contact 95 is moved away from contact 93 bythe spring 81. Contacts 93, 94 are momentarily closed in a similar manner by movement of lever toward dash pct 89.

Accordingly, each time the circuit between conductors I2, '13 is closed by operation of the power change sensing unit I4, relays 50, 5I are reset by solenoids 10, II so that a leaning out cycle may occur upon de-energization of solenoids 42, 19, II and upon closure of contacts 30 due to low engine temperature or upon closure of contacts 22 due to absence of detonation.

Solenoid 42 is also operated to disabl the automatic control system and open valve I0 each time unit 74 is actuated. The operation of the solenoid is momentary if either contacts 93, 94 or 93, 95 is closed but the solenoid is continuously energized if the engine power is not within the predetermined range of automatic operation, as indicated byclosure of contacts I00, I04 or I00, I05.

The time delay switch 44 is an optional feature and serves to reset relays 50 and 5| a predetermined interval after each enriching cycle to permit establishment of a subsequent leaning out cycle before a power change occurs. Thus, when contacts 23 or contacts SI are closed to cause operation of the motor I5 and enrich the fuel mixture, it has been previously pointed out that either relay 50 or relay 5I is operated to prevent a subsequent leaning out cycle until the relay is reset by operation of power change sensing unit I4. Ordinarily, power changes occur with suflicient frequency that it is not necessary to provide for the case where a leaning out cycle should occur after an enriching cycle but prior to the next operation of power change sensing unit I4. However, in some cases, this result is desirable and it may be effected by the use of time delay switch 44.

The operation of switch 44 is to reset relays 50 and 5| without operating solenoid 42, this action occurring a predetermined interval after an enriching cycle resulting from closure of contacts 23 or contacts 3I. A suitable circuit arrangement for accomplishing this result is shown in Figures 2 and 3 wherein it will be noted that a polarized relay H0 is connected in the circuit between the terminal 34 and a motor terminal 43 of Figure 1. The armature III of the relay is biased to the full line position shown in Figure 2 by a spring H2 and, when current flow -switch -member I I4.

shaft I29.

"through therelay in such direction as to cause the' motor I5 to lean out the 'fuelmixture, the 'relay II'O is notactuated. However, 'when'current flows through therelayinsuch*direction asto cause 'motor I5 to enrich th fuel mixture,

"relay I-I'0 is actuated and thearmat'ure' I I I moves to the dotted line position of Figure *2, 1 thereby engaging a' hinged portion I I 3' of i a snap action The switch I14 is not actuated by this movement of the armaturesince the hinged portion II3 merely'swings out of the'path of the armature. 'H'oweverywhen'the *enriching cycle is completed, the current flowing th'roughrela'y-I I is cut ofi'an'dthe armature is-returned to-its full'line position by spring I I2,

so that it again engages the'hinged'portion H3. The member I I4 "is provided with an 'overcenter *spring I I5 so that the 'secondengagement of theportion -I I3 by the armature III causes a contact IIS-tomoveby snap action into'enga'gement'with "a'conta'ct I I1. This closes a circuit including acurrentsource II'8*and a motor II9 thereby causing the motor to rotate a shaft" I23 through a gear box I2I. A drum controller unit I22 is rot'atable'with the shaft-and; after a predetermined intervalpaconducting'shoeI23 of the controller bridges contacts I24 and I25, there- :by completing a circuit through conductors I5 :and -lt the current source 11, and a solenoid The "resultant energization "of solenoid I26 nioves 'themember H4 in a counter-clockwise "direction into engagement-'withastop I21, thereby breaking the circuit between contacts IIS,

Accordingly, each timethe reversible motor I5 is operated to enrich the "fuel'mixture, the relay IID of time delay unit "I4 is operatedat'theend of the enriching cycle and, after a 'predetermined time interval contacts I24, 'I25'a're closed with the result that solenoids "l0- and I I [Figure *1, are energized to reset relays 5'3 "and 5l'for a 'subsequent leaning outcycle. In soine instances,

' this "permits substantialfuelsavings, particularly whereoperation of the'en'gineis'such'that power changes are of infrequent'occurr'ence.

As an optional feature, Imay"al'so' provide a thermostatic'switch 39'which disables the con-- "trol system should the enginecarburetor, air, or

mixture temperature 'riseto an "unsafe value due to abnormal flight orweather conditions. Asa-n additional optional feature,-I mayprovide the intermittent switch flfl, which may simply be a constantly driven drum controller, to'periodircally interrupt'the'current supplied 'to motor I5 in order to prevent the enrichment or leaning "out-ofthe fuel mixture to exceed the 'limits'set up by the setting ofcontacts 22; '23, 30, and '3 I.

"From the "foregoing description, the opera;-

-tionof the'complete system will now be apparent "to those skilled in the art. 'Assum-irig' that-main control switches 38 and39 "are closed and "that the engine is operating within the predeter- -mined power range determined by the setting of switch I31, whenever the engine'temperature'becomesexcessive or whenever detonation "of more "scription isillustrative only andis not intended than a predetermind amplitude occurs "in the cylinder or cylinders associatedwith detonation meter I6,""contacts 23 --orcontacts-3 I are closed to effect'op'eration of the motor I 5 and thereby enrich "the fuel mixture to overcome such --detonat'ion'br excessive, temperatures. 7 When fa power change' occ-urs within'said predetermined power range;the unit' K is-operated andsolenoid 42 is 'niomentarily actuated to provide a rich -fuel mixture while the power change is" occurring. The powercha'ngealso actuates" solenoids '10 and I I to eflectmlosur'e" fo'relay contacts -54, '55', '59,"and"6il. As a-result; the'm'otor i5 is" operated to-leantout the -fuel mixture in response to'su'bsequent closure "of contacts" 30 due to 'excessively' low engine temperatures-chin response to subsequent" closure-of-contacts "22 g-dueto "absence of detonation inthe engine cylinder. -It will-be-noted,=however, that'if eithericontacts23 or contacts "3| '-are closedprior 'to the closure Ofcontacts 22 or contacts 3Il,*one-of the relays 5055 I is "operated to disaiblethe" leaningout circuits" until the relays areresetby -a subsequent 'actuation'of "power change unit 14. "Optionally, time delay switch '44 maybeprovi-de'dtoreset the relays a predetermined intervalafter'each enriching cycle without the-occurrence of a-power change.v "When the enginepowerisoutside the aforesaid predetermined-power range, switch IiII -is-closedand unit I4 is'continuously-actuated, thereby to energize solenoids "42; IE-and II with the: result "that the automatic controlsystemis disabled until the power level once again is within the predetermined range, The described ,energization of solenoids 'II1,- I I: also closes-relays '50, 5I to prepare" the system for a subsequent leaningiout cycle.

-It 'will" be" apparent that; the described system effects the metering of fuel "to the "enginein such iashion that "t-he'fuel-air ratio alwaysh'as a proper I value to prevent detonation or excessive engine temperatures while still utilizing the 'leanestpossible fuel mixture. Suchregulation of thefuel-air ratio also minimizes; the disadvantages resulting fromtorching of the ex haust or the-loss-of substantial powerdue to supplying excessive fuel to the; engine cylinders. {The system of this invention "also =provides;means for equalizing the performance --of a number of engines by operating all of these engines under optimum fueha-ir conditions despite unavoidable variations inthe manufacture ofthe carburetors. "Although the systemhas --been primarily described in connection withaircraft engines-it will be -obvious that many embodiments are appl-icable to'many other types of engines, such as automobile engines. When appliedto automobile engines, other-power change sensing means may be utilized than thebellows chambers 82, 83 providedthatcontrol lever moves in accordance with changes in the power output of the engine.

While the invention "has been described in connection with a present, preferred embodiment thereof, it is to be understoodthat this de- -=mixtureto be fed toan internal combustion engine, meansfor sensing detonation in a "cylinder of saidengine, means for sensing engine temperature, -and--acontrol unit for said valve actuated by both of said sensing means, to maintain predetermined conditions of detonation and engine temperature through regulation of the fuel-air ratio of the fuel mixture.

2. In a fuel metering system, in combination, a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for sensing detonation in a cylinder of said engine, means for sensing excessive engine temperatures, and a control unit for said valve actuated by both of said sensing means for enriching said fuel mixture when necessary to prevent detonation or excessive engine temperatures.

3. In a fuel metering system, in combination,

I a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for sensing detonation in a cylinder of said engine, means for sensing engine temperature, first control means to operate said valve and lean out the fuel mixture, said sensing means permitting operation of said control means only when the engine temperature is below a predetermined value or when no detonation is occurring, second control means actuated by said sensing means to operate said valve and enrich the fuel mixture when detonations occur or the engine temperature becomes excessive, means disabling said first control means upon operation of said second control means, power I change sensing means, and means for restoring said first control means to operative condition upon each operation of said power change sensing means.

4. In a fuel metering system, in combination,

a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for sensing detonation in a cylinder of said engine, means for sensing engine temperature, first control means to operate said valve and lean out the fuel mixture, said sensing means permitting operation of said control means only when the engine temperature is below a predetermined value or when no detonation is occurring, second control means actuated by said sensing means to operate said valve and enrich the fuel mixture when detonations occur or the engine temperature becomes excessive, means disabling said first control means upon operation of said second control means, power change sensing means, means for restoring said first control means to operative condition upon each operation of said power change sensing means, and a time delay unit independent of said power change sensing means to place said first control means in operative condition a predetermined interval after said second control means has been actuated.

5. In a fuel metering system, in combination, a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion. engine, means for providing an electric current representative of engine temperature, a solenoid operated by said electrical current to close a first set of contacts when the engine temperature is too high and to close a second set of contacts when the engine temperature is too low, means for providing a second electrical current representative of detonation in a cylinder of said engine, a solenoid operated by said second electric current to close a third set of contacts when detonation is occurring and to close a fourth set of contacts when no detonation is occurring, a reversible motor operatively connected to said valve, a control circuit actuated by said first and control circuit including said second and fourth sets of contacts for operating said motor to effect leaning out of said fuel mixture.

6. In a fuel metering system, in combination, a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for providing an electric current representative of engine temperature, a solenoid operated by said electrical current to close a first set of contacts when the engine temperature is too high and to close a second set of contacts when the engine temperature is too low, means for providing a second electrical current representative of detonation in a cylinder of said engine, a solenoid operated by said second electric current to close a third set of contacts when detonation is occurring and to close a fourth set of contacts when no detonation is occurring, a motor operatively connected to said valve, a control circuitactuated by said first and third contact sets to operate said motor and thereby enrich the fuel mixture, and a-second control circuit including said second and fourth sets of contacts for operating said motor to effect leaning out of said fuel mixture, means actuated by said first circuit for disabling said second circuit each time the former circuit is actuated, and a thermostatic switch connected in circuit with said motor to prevent operation thereof when the engine temperature is excessive.

7. In a fuel metering system, in combination, a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for providing an electric current representative of engine temperature, a solenoidoperated by said electrical current to close a first set of contacts when the engine temperature is too high and to close a second set of contacts when the engine temperature is too low, means for providing a second electrical current representative of detonation in a cylinder of said engine, a solenoid operated by said second electric current to close a third set of contacts when detonation is occurring and to close a fourth set. of contacts when no detonation is occurring, a reversible motor operatively connected to said valve, a control circuit actuated by said first and third contact sets to operate said motor and thereby enrich the fuel mixture, and a second control circuit including said second and fourth sets of contacts for operating said motor to effect leaning out of said fuel mixture, means for disabling said second circuit each time the first circuit is actuated, power change sensing means, and means actuated by said sensing means for restoring said first circuit to operative condition each time a power change occurs.

8. In a fuel metering system, in combination, a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for providing an electrical current representative of engine temperature, a solenoid operated by said electrical current to close a first set of contacts when the engine temperature is too high and to close a second set of contacts when the engine temperature is too low, means for providing a second electrical current representative of detonation in a cylinder of said engine, a solenoid operated by said second electrical current to close a third set of contacts when detonation is occurring and to close a fourth set of contacts when no detonation is occurring, a reversible motor operatively con- 11' nected-to-said valve; acontrol circuit actuated by' said first and third contact setsto operate said motorand thereby enrich the fuel mixture,- 'a= second-control circuit including; said second and fourth sets of contactsforoperatingsaidmoton to effect-leaning outof said fuel mixture, a=pair of relays each having a setof normal-ly closed contacts connected incircuit with said secondcontacts and-a set ofnormally"closed-contactsconnected in circuit with said fourth "set of--'con-- tacts; the coils of said relays being connected in circuit; respectively, with said first set of contacts and said third set of contacts whereby the secondcontrol circuit-is disabled'lwhen thefirst control circuit is actuated to" energize one-of said relays and open its normally closed contacts,- power change sensing a means, and solenoids actuated by; said power change-sensingmeans toclose both sets of normally closed contacts- -each time a power change occurs;

9 In-a fuel metering "system, incombination; a valve for regulating the-fuel-air ratio of-afuel mixture to be fed to 'an internal "combustion-em gine; means for providingan electrical current representativeofengine temperaturea solenoid operated by-said electrical current to close a first set-of contacts when the engine temperature is 'too'high andto close a second set of 2 contacts when the engine temperature is-too low,' means for providing a second electrical 1 current: representative of detonation-in a--cylinder of said engine, a solenoid operated by said secondel'ectrio-current to-close'athird set of: contacts when detonationis occurring and "to close a fourth set of" contacts when no; detonation is: occurring; a.

reversible motor operativelyconnected to: said va-lve; a control circuit actuated bysaid first and third contact 1 sets to operate said motor: and thereby enrich thefuelmixture, asecond Lconl trol'circuit including-said second and-fourth :sets of contacts for operating said motor to effect leaning out-ofsaid-fuel mi-xture; a pair of. relays eachhaving a normally closed set of con-.. tacts connected in circuit with saidsecondcon tactsand-a normally closed-'set of contacts connectedin circuit with said I fourth I contactsthe coilsofsaid relays being connected in circuit; respectively, with saidfirst contacts and said third contactswhereby the second 'control' circuit" is'disabled' When-the-fi'rst control circuitis actuated to energize one of said relays-and there byopen its normally; closed contacts; power: changesensing means,- solenoids actuated by-said' power changesensing means to close both of -said' relays eachtimea power change occurs, anda switch connected incircuit with saidmotorto-im termittently' make and break the control circuitstherefor. I

10. In a fuel metering system, in combination; a valveforregulating the fuel-air ratio of a fuel mixture'to' be fed to an internal combustion engine, means for providing an electric currentrepresentative of engine temperature, asolenoid operated by said electricalcurrent to close-a first set of contacts when the engine temperature is too=high and-to close-a secondsetofi contacts when the engine temperature-istoo low, means: forproviding a second electrical current repre sentative' ofdetonation in a cylinder of' said engine,- a solenoid operated by said'second electric current to close a thirdset of contacts when detonation is occurring and" to close a fourth set' of contacts whenno detonation is occurring. a reversible motor" operatively 'connected' to saidvalve, a-control circuit-actuated by said first" and third contactsets, to operate said motor and thereby enrich the fuel mixture, a second control circuit including: said second and fourth sets of contacts for operating said-motor to. efiect leaning-outiof said fuel mixture, a pair of relays each having a set: of normally closed contacts connected in: circuit with said second contactsanda setiof normally closedcontacts connected powerchange sensing. inea-nsxto close both sets of normally closedxcontacts: each, time a power change. occurs,. and.;a thirdgsolenoid'actuated by.

saidzpowenchange sensing means to operate said valVeandenrichsaid fuel mixture while apower change: is: occurring:

lL-In aiuelmetering system; in combination; a-..va=lve; for regulating the fu-ela-ir ratio of a fuel mixture to, be fed" to. an. internal combustion engine; 11183115101 providing" an electric current representativeoffengine temperature, a solenoid operatedzhy said electrical current to close a first.

set .Of contacts: when the engine temperature is too high &1'1d".l30 .10$8 asecond set of contacts whenlthe engine temperature iatoo low, means for: providing-a second electrical current representa-tiveof detonation" in a cylinder of said engine, a solenoid operated by said second electric current to close a-third set of contacts when detonation isgoccurring and to close a fourth set of, contacts when-n0 detonation is occurring. a reversibleamotor operatively-connected to said valve; a control circuit actuated by said first and third contact sets to. operate said motor and thereby enrich thefuel mixture, a second control circuits including saidsecond and-fourth sets of contacts-foroperatingsaid motor to effect leaningoutof said fuel mixture, a pair-of relays each having. 'a-normally closed set of contacts connected'; in; circuit: with saidsecondcontacts and a normally closed set of:contacts= connected in circuit withwsaidfourth contacts, the coils of said relays being connected in circuit,- respectively. withisai-dr first set ;,of contacts and said third set of contacts-whereby-the second control circuit is disabled 'when the first control circuit is actuatedto energize one .of said relays and thereby open -itscnormally closed contacts, power change sensing; means; solenoids actuated-by said:power change sensing" means to CIOSS'bOth' sets. of ,normallyiclosed contacts each: timega' power'change occurs, and a third solenoid actuated-by said powcrchange sensing means to momentarily operatesaid-valveand-enrich thefuel mixture when a normal power'cha-nge occursandtto operatesaid; valve continuously: when the engine power is abovezor below a predeterminedrange.

12. A time de1a-y;- switch unit comprising a;

position; means-urging; saiddrum toward said.

predetermined position, and a solenoid actuated by closure ofsaid contacts to movesaid snap ac-- tion switch to open position.-

13. In a fuel metering system, in combination, a valve for regulating the fuel-air ratio of a fuel mixture to be fed to an internal combustion engine, means for sensing detonation in a cylinder of said engine, means for sensing excessive or subnormal engine temperatures, and a control unit for said valve actuated by both of said sensing means for enriching said fuel mixture when necessary to prevent detonation or excessive engine temperatures, and for leaning out said fuel mixture responsive to subnormal engine temperatures or lack of detonation.

EMIL A. MALICK.

14 REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS 

